[jnymarkp]

Hi all - and a happy new year to all of You

I'm in the planning to build a CNC Mill from scratch and need your opinions about my choise of rails.
I have ended up with a gantry mill, with moving gantry. X, Y and Z rails would be 50-60cm each, and want to do milling in wood, aluminium and soft steel.

I have been looking at THK and IKO linear rails, but they seem somewhat pricey for my budget.

Lattely i have found these supported rails, sold as a complete set for 3 axis (rails, ballscrew and supports).

cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&item=250480359788

But im in doubt about if they are strong enough to withstand the forces that would be applied to them?

Anyone had any experience with these?

Thanks in advance

Jesper

[veteq]

Hey Jesper,

Have a look at the rails off Hiwin HG15 more then strong and rigid enough for almost all hobby designs. make sure you place the wagons as far apart as possible.

google for damencnc, they sell the block for 40 euro a piece and the rails is also nicely priced.
Why 60 cm for Z, go for 20 and make you design a lot more rigid

Regards,

Roy

[jnymarkp]

Hey Jesper,

Have a look at the rails off Hiwin HG15 more then strong and rigid enough for almost all hobby designs. make sure you place the wagons as far apart as possible.

google for damencnc, they sell the block for 40 euro a piece and the rails is also nicely priced.
Why 60 cm for Z, go for 20 and make you design a lot more rigid

Regards,

Roy

Hi Roy

Thanks for your answer.

Have had a look at them,- but they seem a bit pricey to me. Transportation to Denmark alone is verry high.
Or is it just me being a cheap a.. mf? :s
The dimentions i am talking about are for the rails, and the 25-30cm movement on Z-axis are ment to be used when adding automatic toolchanger lateron.
Have big plans for this machine, including automatic toolchanger, quick mill/lathe conversion, 4 and 5'th axis.
The rails that i have found on ebay are just the right price for my budget, thats why i'm asking about them being strength enough.

Still trying to figure out how to do it, but i think its coming to me

Regards

Jesper

[veteq]

Hey Jesper,

You are right, ebay is a cool place, bought for myself 12 runnerblocks and 6 times a Precision series rail off 230mm. They are from THK HSR12`s.

Bought them NEW on ebay for 400 dollar total incl shipping, no taxes, postdude just handed them to me!!!

Same for 3 times a Kuroda GP1002 preloaded ground c3 ballscrew, New and machinend to 272mm. Total 400 dollar.

Best is to watch ebay for a long time while you are thinking about the design and make good fast and cheap dissicions.

look for rails with 4 contactpoint balls, not 2.

Think 15 or 20 will be more then enough, offcourse the structural design counts also.

Regards,

Roy B.

FA-parts (shop) is a good one on ebay

[jnymarkp]

Hi again Roy

Yup - love lurking around on Ebay - lots of cool stuff to get there.

Just bought myself a book about homemade CNC mill for modelmaking

Can see you have found some verry nice prices over there.
Unfortunately the shipping costs to Denmark are usualy around 50-60$US per item

I have noticed something about the supported rails and bearing blocks that i have been looking at.
Their dimentions are shown with +- 0.02mm.
That dosn't seem verry accurate to me....

Maybe that explains their pricing ;O)

Regards

Jesper

[agapios]

Hi again Roy

Yup - love lurking around on Ebay - lots of cool stuff to get there.

Just bought myself a book about homemade CNC mill for modelmaking

Can see you have found some verry nice prices over there.
Unfortunately the shipping costs to Denmark are usualy around 50-60$US per item

I have noticed something about the supported rails and bearing blocks that i have been looking at.
Their dimentions are shown with +- 0.02mm.
That dosn't seem verry accurate to me....

Maybe that explains their pricing ;O)

Regards

Jesper

hi

a good web is http://www.igus.eu is have and a life calculation program to calculate the forse's



Regards


Agapios

[veteq]

Supported rails and squre rails are 2 different motion parts, 1 for hobby and the square ones for proffesional use. please forget the round rails, supported or not.
Better to buy second hand ones then going for new round rails.

Shippingprice is the same for me, but if the part is so cheap in comparisson with new price i just pay it.